1. Field
The present invention relates to mobile communications and, more particularly, to a method and system for providing location based services to a mobile subscriber terminal roaming outside the network to which it subscribes.
2. Description of Related Art
Cellular wireless communication is an increasingly popular means of personal communication in the modern world. People are using cellular wireless networks for the exchange of voice and data over cellular telephones, Personal Digital Assistants (“PDAs”), cellular telephone modems, and other devices. In principle, a user can seek information over the Internet or call anyone over a Public Switched Telephone Network (“PSTN”) from any place inside the coverage area of the cellular wireless network.
An important feature of contemporary cellular wireless networks is an ability to locate the geographical position of a mobile-subscriber terminal. Such a feature was developed, at least in part, to assist emergency services in locating a mobile-subscriber terminal. For example, in the United States, the Federal Communications Commission (“FCC”) has mandated the implementation of “Enhanced 911” (“E911”) services to facilitate the location of mobile-subscriber terminals.
The E911 mandate was divided into two phases. According to Phase 1, the location must be identified with an accuracy of at least a cell and sector. Because this information is typically maintained by a wireless cellular carrier in a subscriber's home location register (“HLR”), Phase 1 presented little technical challenge. According to Phase 2, the location must be provided with an accuracy of at least 50 meters 67% of the time and 150 meters 95% of the time for handset based location techniques (100 and 300 meters for network-based location techniques), which is far more granular than the cell and sector information maintained in the HLR. In response, the Telecommunications Industry Association (“TIA”) has proposed a new standard for “Enhanced Wireless 9-1-1, Phase II” or “TIA/EIA/IS-J-STD-036” (“J-STD-036”), American National Standard Institute, Jul. 11, 2000, the entirety of which is hereby incorporated by reference.
In order to achieve the accuracy specified by Phase 2, a cellular wireless network may employ special position determining equipment and techniques. Alternatively, a mobile subscriber terminal itself may employ a position determining system such as a GPS system and may relay its position to the network, for reference by the emergency services. The emergency services may then use the position of the mobile subscriber terminal to help assist a user of the mobile-subscriber terminal.
Cellular wireless carriers and third-party application providers have recognized the commercial significance of this new-found location information, well beyond use of the information for emergency services. In particular, knowing where a mobile subscriber terminal is located (e.g., mobile positioning information), the cellular wireless carriers and third-party application providers may now provide a wide range of valuable location based services.
Location based services are applications that supply information as a function of a geographic trigger. The geographic trigger might be a town name, zip code, street, a position of a mobile-subscriber terminal, and/or the position of a vehicle. In other words, location based services can be generally defined as the ability to find a geographical location of a device or person and provide services based on this geographical location. For instance, using mobile positioning information, a location based service can provide to a mobile subscriber terminal directions to a local restaurant, sporting arena, pub, etc. Location based services may also include business application such as location-sensitive billing, traffic updates, fleet management, asset tracking, and people tracking.
However, each wireless carrier only provides such services to their own subscribers. Thus, even though a mobile subscriber terminal may be able to carry on a voice and data communication when roaming outside the network to which it subscribes, requests for location based services from these non-subscribers are not carried out. This is due to, in part, technological differences between the service providers, federally and contractually determined delineated coverage areas, access to local geographical information, etc. Further, the lack of intersystem location based services is amplified when the mobile subscriber terminal roams across international boundaries, where geographical information for the foreign country is not maintained or available to the service provider of the mobile-subscriber terminal.